Compact discs have become a popular recording medium for digital information including audio program material as well as other data such as computer software and the like. A compact disc (CD) includes a reflective optical surface which is encoded with the digitally encoded data. The optical surface is read with the aid of a laser, which impinges a beam onto the optical surface. Reflections of the beam are captured and converted into digital signals representing the digital information on the disc. Thus, it will be appreciated that faithful reproduction of the information on the disc may be impaired by scratches, dust, or other imperfections introduced into the optical surface during shipping, storage, or handling of a CD.
Because of the need to protect the optical surface of a CD, various CD storage devices, both rigid and flexible, have been developed. An example of a rigid storage container is the jewel box, which consists of two pieces of molded polycarbonate hingedly connected along one side. A styrene tray with a center hub is snap fit inside one of the polycarbonate pieces, the center hub being formed to engage the center aperture of a CD and hold the CD with the optical surface not in contact with any portion of the box. Jewel boxes have an advantage of being suitable for holding a CD not only during shipment from a manufacturer, but also for after-market storage by the consumer. However, although the jewel box serves to protect the CD, it suffers from several disadvantages. The box is difficult to open, and it is difficult to remove the CD from the center hub without bending the CD. The box is also relatively fragile, resulting in breakage of the hinges or the polycarbonate pieces when accidentally dropped. Furthermore, the jewel box is expensive to manufacture because of the three-piece construction and the need to manually assemble the parts. Finally, the jewel box is relatively bulky, generally having a thickness many times the thickness of the CD itself.
As an alternative to the jewel box, various types of flexible CD storage containers have been developed. One example of a flexible CD container is shown in my U.S. Pat. No. 5,462,160, which is incorporated herein by reference. The container is comprised of a first flexible sheet to which is joined a nonwoven fabric sheet, with an overlying second flexible sheet joined along its edges by heat lamination to the first flexible sheet through the nonwoven fabric to create a CD storage area. Access to the storage area is provided by a flap cut into the second flexible sheet within the boundary of the bond to permit insertion of a CD into the storage area so that the optical surface contacts the nonwoven fabric. Although the container described in the '160 patent provides excellent storage protection for the CD, it has at least two notable drawbacks. First, the container is primarily useful as an after-market storage container. It is not well suited for use as a shipping container, because a manufacturer would have to resort to a relatively expensive procedure of manually inserting a CD into the container. Second, the heat lamination process for bonding the edges of the sheets together tends to introduce distortion into the sheets, resulting in a somewhat wavy appearance.
Yet another flexible CD container is marketed by the assignee of the present application under the trademark "ADHESIVEPAK". The container is comprised of three sheets joined along three common edges, the top edges of the sheets being left unbonded. This container has a first pocket defined by a first sheet and an intermediate sheet and a second pocket defined by the intermediate sheet and a second sheet. A CD is stored in the first pocket with the optical surface in contact with the intermediate sheet. Graphics material may be stored in the second pocket. The first sheet is transparent to permit viewing of graphics printed on the non-optical surface of the CD, and has a perforated cut line wider than a CD diameter to define a flap which may be partially separated from the remainder of the first sheet to create an opening for insertion and removal of a CD. At one side of the bottom of the cut line, the line is fully cut to form a tab portion of the flap which may be grasped and pulled to initiate breaking of the perforations. The intermediate sheet is a composite of a flexible layer bonded to a nonwoven fabric layer, with the nonwoven fabric facing the first sheet. The second sheet is a composite of an adhesive-backed vinyl layer and a paper layer having a glossy surface in contact with the adhesive side of the vinyl layer. The paper layer may be peeled off to expose the adhesive side of the vinyl layer, so that the container may be pasted onto a page in an album, book, or the like. Openings to the first and second pockets are defined by slits in the intermediate and second sheets, respectively, which slits are spaced inward of a top edge of the container. A strip of adhesive runs adjacent to the top edge, so that when the container is pasted down onto a page, the openings to the pockets are effectively closed. The ADHESIVEPAK container is primarily intended as an after-market storage device, and the operation of pasting the container onto a page is intended to be carried out by the end user or purchaser of the container. After the container has been pasted down onto a page, a CD is then inserted into or removed from the first pocket by breaking the perforations of the flap cut line to create an opening in the first sheet. However, since a CD may be inserted into the container without disturbing the perforations of the flap cut line, the ADHESIVEPAK container could also be used as a shipping container. Nevertheless, the container has the disadvantage that the CD storage area remains open at its top opening until the container is pasted onto a page, which may allow the CD accidentally to slip out of the container during shipping. The unsealed opening may also permit infiltration of foreign material into the container during shipping or after-market storage and handling of the container, which may lead to scratching of the CD optical surface.
Thus, prior flexible containers for compact discs have not been amenable to being formed, filled with a CD, and sealed closed on all edges in one continuous automated operation.